The invention relates to a device for positioning at least one optical component within an endoscopic system, with a housing, through which runs an optical axis of the endoscopic system and in which the at least one component is arranged, which can be pivoted into the beam path of the endoscopic system about a pivot axis and which can be pivoted out of the beam path.
Such a device is e.g. known from DE-A-197 13 276.
Optical components are understood in the present invention as e.g. lens, filters, field stops and similar equipment, which are used in endoscope optics.
A special application of the present invention is the use of such a device in an endoscopic system for photodynamical diagnosis, photodynamical therapy or for fluorescence diagnosis.
In photodynamic diagnosis, light of a special spectral composition generated in a light source is coupled into the body and directed onto tissue to be examined. Before, a photo sensibilisator or marker material is instilled into the tissue to be examined. By irradiation of the tissue being enriched with the photo sensibilisator with stimulation light, a light-induced reaction is provoked, by which fluorescence radiation from the tissue region to be examined is emitted. There are, to this end, photo sensibilisators, which enrich in tumor tissue stronger than in healthy tissue. By means of the intensity differences of fluorescence radiation it is made possible, in that way, to differentiate tumor tissue from healthy tissue with high contrast. The fluorescence light and the stimulation light are in different spectral regions.
To allow a particularly good observation with high contrast of the tissue to be examined, which observation is free from a background radiation of the stimulation light, which superimposes the observation light, a color filter is brought into the observation beam path, i.e. into the beam path of the fluorescence light, the color filter having a high transmission in the spectral region of the fluorescence light, while its transmission is low in the region of the illuminating light or in the stimulation light. As light sources, also white light sources are often used, wherein a filter is also brought into the illuminating beam path, which has a pronounced transmission in the spectral region of the spectral region that is suitable for the stimulation of the photo sensibilisator.
A beam path is understood in the present invention, thus, as the beam path of illuminating light, which propagates from proximally to distally, and/or of observation light, which propagates from distally to proximally.
As, with the same endoscopic systems, not only an observation of fluorescence light shall be possible, but also a common observation of the tissue region with white light, such color filters need not only as simply as possible to be brought into the beam path, but also to be brought out again.
To this end, filters are known, which can be mounted onto the endoscope, i.e. on its distal end. Such filters are, however, cumbersome to handle. For mounting or detaching of such a filter it is, apart from that, necessary to remove the endoscope, during the diagnosis or therapy, out of the body, which extends the examination or treatment of the patient. Moreover, such mountable filters can easily get lost.
The device known from DE-A-197 13 276 mentioned at the outset for the positioning of components within endoscopic systems has, in an embodiment, a turret wheel, which is rotatable about a housing-centered axis. The turret wheel carries several optical components, which are distributed in a plane and which can be pivoted about the centered axis as the pivot axis into the beam path of the endoscopic system. The pivot axis is arranged eccentrically parallel to the optical axis. This arrangement requires, however, that the optical axis of the endoscopic system must be arranged eccentrically with respect to the housing center axis. In the case of an endoscope, this means that the housing of the device is not arranged concentrically with respect to the endoscope shaft axis, which is, however, desirable.
If the configuration mentioned before was modified in that direction that the housing of the device surrounds concentrically the optical axis of the endoscopic system, the diameter of the housing would have to be enlarged by the double, when the diameter of the turret wheel remains unchanged, the diameter not being able to be reduced in size due to the preset size of the optical components, so that there would be the disadvantage of a radially very bulky device.
It is, thus, the object of the present invention to improve a device mentioned at the outset in such a way that pivoting in and pivoting out of the at least one optical component within the endoscopic system is possible, without the device being bulky.
The object of the invention is achieved by a device for positioning at least one optical component within an endoscopic system, comprising a housing, in which said at least one optical component is arranged, and through which runs an optical axis of said endoscopic system, a beam path of said endoscopic system extending along said optical axis, wherein said at least one component can be pivoted into said beam path of said endoscopic system about a pivot axis and can be pivoted out of said beam path, wherein said pivot axis is arranged obliquely with respect to said optical axis.
While in the prior art, in particular in the known device, always the concept was maintained to arrange the pivot axis, about which the at least one optical component can be pivoted into and out of the beam path, parallel to the optical axis, it is provided in the invention to arrange the pivot axis obliquely to the optical axis. Pivoting the at least one optical component about a pivot axis, which runs obliquely with respect to the optical axis, equals a folding of the component. Pivoting in and pivoting out the component about a pivot axis, which runs parallel with respect to the optical axis requires namely that the pivot axis runs eccentrically with respect to the optical axis, which always requires a radial minimum construction size of the device. When the one or several components are folded about a pivot axis, which runs obliquely with respect to the optical axis, however, a radially narrow construction can be reached, because the component has to perform no movement in circumferential direction of the housing. In the simplest embodiment, one or several components can be individually mounted pivotably in the housing, e.g. three components in a triangle arrangement seen in cross section at axially equal position, or four components may form e.g. a square arrangement at axially equal position, or individual components can be provided axially one behind the other pivotable about individual own pivot axes. The configuration of the device according to the invention allows in an advantageous manner to arrange the housing, no matter if in round or in square configuration, with reference to the optical axis in such a way that the optical axis transverses approximately centrally through the housing, without that it is necessary to have to configure the housing in large construction to this end. In this way, several components can be arranged in the housing, which in a space-saving way can be respectively individually or together pivoted into the beam path of the endoscopic system and pivoted out of the beam path. A pivot axis arranged obliquely can e.g. be arranged in an angle of 30xc2x0, 45xc2x0, 60xc2x0 or 90xc2x0 or in intermediate angles of these angles with respect to the optical axis, wherein a corresponding arrangement of the optical component with respect to the pivot axis can be chosen, if it is intended for reasons of minimization of the reflection losses and the beam mismatch to have the optical component with its light passage surfaces orthogonal with respect to the optical axis. The device of the invention can advantageously be integrated in an endoscope, wherein then the housing of the device is an integral part of the housing of the endoscope, having the advantage that also the endoscope can be configured with a radially narrow structure in the region of the integrated device.
The object underlying the invention is in that way completely achieved.
In a preferred embodiment the pivot axis is arranged approximately orthogonal with respect to the optical axis.
This measure has the advantage that a simply designed construction of the device is reached, because when the pivot axis runs approximately orthogonal to the optical axis also the relative arrangement between the component and the pivot axis can be chosen as a right angle, in particular for the case mentioned at the outset that for reasons of minimization of the reflection losses and of the beam mismatch a positioning of the component pivoted into the beam path orthogonal with respect to the optical axis is to be reached.
In another preferred embodiment the pivot axis is arranged in such a way that the component in the state pivoted out of the beam path comes in an adjacent position with a flat side of an inner wall of the housing.
By this measure, a particularly space-saving mechanism for pivoting in and pivoting out for the at least one component is created. The housing of the device can be so radially narrow in this embodiment that between the clear diameter provided for the beam path within the endoscopic system and the inner wall of the housing just a gap remains, in which the at least one component in its position pivoted out, i.e. in its resting position, finds enough space. In resting position, the component is then essentially parallel with respect to the optical axis of the endoscopic system. An imaginable simple design is to arrange the pivot axis at an edge of the component and to mount the component like a flap into the housing.
In another preferred embodiment the at least one component is fixed on a carrier, which is fixed at the housing pivotably about the pivot axis, and which is in its cross section configured approximately in L-shape, wherein a first leg of the carrier carries the at least one component, and a second leg is articulatedly fixed at the housing.
It is here advantageous that by means of the carrier a stable holder for the at least one component is provided, which meets the requirements of stableness in permanent operation when pivoting in and out is performed several times. The carrier can in this procedure receive the at least one component of the type of a frame, whereby the component, which is sensitive against mechanical influences is protected on its edge side. The L-shaped configuration of the carrier has the advantage that the carrier can be located in a radially space-saving manner around the beam path in the housing, without interferingly influencing the light passage.
In this procedure, it is preferred if in the housing at least two pivotable carriers are arranged, which each carry at least one component, and which are pivotable independently of each other.
It is here advantageous that with the same device alternatively different components, e.g. two or more optical filters with different spectral transmission characteristics can be alternatively or simultaneously pivoted into or out of the beam path of the endoscopic system.
It is here preferred if the carriers are coupled with each other in such a way that, when the at least one component is pivoted in, the at least one other component is pivoted out, and vice versa.
In this configuration, it is advantageous that a pivot mechanism and/or a flap mechanism is created, which allows an advantageously simple operation. In this embodiment, it can be switched between two or more operating positions by a single actuation mechanism, in which, respectively, e.g. a component is pivoted into the beam path and the other components are pivoted out of the beam path.
In another preferred embodiment the carriers are arranged axially in an approximately same position.
By this measure, not only a radially, but also an axially small device is created. In particular in connection with the L-shaped embodiment of the carriers mentioned before, two of such carriers can be arranged and mounted pivotable in a space-saving way symmetrically to each other in the housing.
Alternatively to that, it is also preferred, however, if the carriers are arranged at axially different positions.
By this measure, the advantage is achieved that two or more components can be simultaneously pivoted into the beam path. For example, the one carrier may carry a field stop, the other carrier may carry a color filter and the third carrier may carry a heat protection filter, which can be simultaneously brought into the beam path axially arranged one behind the other, which can make sense depending on the application of the endoscopic system.
In another preferred embodiment the carrier carries several components which are distributed in pivot direction over the circumference.
In this embodiment only one pivotable carrier is provided, by which alternatively individual optical components can be pivoted into the beam path and out of the beam path, whereby advantageously with only one carrier several components can be arranged pivotably in the housing, which advantageously means a reduction of the number of parts of the device. In such an embodiment of the carrier, the pivot coupling mentioned before is also achieved, in such a way that, when the at least one component is pivoted in, the other component or the other components are automatically pivoted out of the beam path.
In another preferred embodiment for actuating pivoting in and pivoting out the at least one component, a magnetic coupling is provided, which has at least one outer movable magnetically active element arranged outside the housing or a magnet and at least one inner magnetically active element arranged within the housing, wherein the outer magnetically active element or the outer magnet and the inner magnetically active element coact through the housing via a magnetic frictional connection.
This magnetic coupling known per se for such devices has, again, the advantage that the housing of the device can be configured hermetically tight closed, whereby the advantage is achieved that the device and, thus, the endoscopic device at which the device is provided, can withstand the conditions in an autoclave, so that it is guaranteed that the device can be cleaned as is required for medical purposes. If it is talked about outer magnets in the following, these can also be replaced by magnetically active elements made of magnetic materials like soft-iron cores, at least in the case when magnets are provided as inner magnetically active elements.
In another preferred embodiment the carrier is configured as a two-armed lever with respect to the pivot axis, the one lever arm of which carries the at least one component, and on the other lever arm of which engages an essentially axially movable force transmission element.
In connection with the pivot axis running obliquely to the optical axis, an actuation mechanism is produced via this lever mechanism with an axially movable force transmission element in connection with the carrier configured as two-armed lever, which actuation mechanism is simple in design for pivoting in and out the at least one component.
It is further preferred if the at least one outer magnet or the at least one inner magnetically active element of the magnetic coupling mentioned before are axially movable, wherein the inner magnet is connected to the force transmission element.
This embodiment of the magnetic coupling differs insofar from the magnetic coupling of the known device, as in the latter both the at least one outer magnet and the at least one inner magnet are configured in a rotatable, but axially not movable way. Different from that, in the present invention the advantage is achieved that in connection with the lever mechanism mentioned before, the movement transmission mechanism from the outer magnet as control unit on the lever mechanism is particularly simple in design because no mechanical components need to be provided in the device, to change a rotation movement of the magnets into an axial movement of the lever mechanism. Thus, the expenditure in design of the device of the invention is considerably reduced.
In another preferred embodiment the magnetic coupling comprises at least two outer magnets, which are arranged on a rotatable ring, in axially different positions, wherein the at least one inner magnetically active element is axially movable and connected to the force transmission element, and wherein the two outer magnetically active elements or magnets can alternatively be brought in magnetic engagement with the inner element by rotating the ring.
It is advantageous herein that further a constructively simple magnetic coupling is created, for which, moreover, no mechanical components need to be provided to change a rotation movement into an axial movement. By the rotation easy to be operated of the outer rotatable ring, which is preferably arranged axially immovable around the housing, an axial to-and-fro movement of the inner magnetically active element is caused by alternative engagement of one of the two outer magnets with the one inner magnetically active element because the two outer magnets are arranged at axially different positions.
In another preferred embodiment the at least one inner magnetically active element is arranged on the carrier itself and coacts directly with the at least one outer magnet for pivoting in and for pivoting out of the at least one component.
In this embodiment of the magnetic coupling there is the advantage that for folding down the carrier, which carries the at least one component, no further force transmission elements are necessary, whereby the construction of the magnetic coupling is further simplified in design and, in addition to that, the danger of functional defects is reduced due to the smaller number of movable parts.
It is here, again, preferred when the at least one outer magnet is movable via a rotatable ring surrounding the housing.
By this measure, again, a simple actuation mechanism for the magnetic coupling is created, by which the at least one component can be pivoted into and out of the beam path in a manner that is easy to operate.
In another preferred embodiment two inner magnetically active elements are arranged, in the form of two magnets, on carriers, wherein the inner magnets, with respect to the pivot axis, are arranged opposite to each other and polarized opposite to each other, and that at least two outer magnets are arranged outside the housing, which are, alternately, movable into a position, in which they coact magnetically with the inner magnets, in order to pivot in and out the at least one component.
This represents a preferred and advantageous embodiment of a magnetic coupling with magnetic elements that are arranged directly at the carrier, in which the turning of the carrier for pivoting in and out is performed by at least two magnetic fields which are opposite directed. Due to the arrangement of the two inner permanent magnets in opposite with respect to the pivot axis, each time, when the at least one other of the outer magnets is brought magnetically into engagement with the two inner permanent magnets, a torque is created that moves the carrier from its previous position, e.g. the position pivoted in, into another position, i.e. then into the position pivoted out.
For the embodiments mentioned before, in which the at least one outer magnet is arranged on a rotatable ring, which serves as actuation element or as operation element for pivoting in and out the at least one component, it is further preferred when this ring has at least two lock-in positions, wherein at least a first lock-in position is assigned to a pivoted out position of the component and at least a second lock-in position is assigned to a pivoted in position of the component.
By means of such lock-in positions in which the ring locks in an audible or noticeable way, the user can decide how far to rotate the ring to arrive from the position pivoted in of the at least one component into the position pivoted out. If a mark is applied on the ring, he can, apart from that, always determine the position of the at least one component.
In another preferred embodiment the at least one outer magnet is a permanent magnet.
The use of a permanent magnet has the advantage that the magnetic coupling can be constructed particularly simple, in particular, no current supplies are required as for electric magnets.
In another preferred embodiment the at least one outer magnet is an electric magnet, wherein the at least one inner magnetically acting element is connected to a back-force spring, if necessary.
The use of an electric magnet for the magnetic coupling is also advantageous because pivoting in and out the optical component can be performed by changing the current direction in the electric coil without an outer regulating unit at the housing of the device being necessary. If necessary, the inner magnetically active element can be connected to a back-force spring and, thus, be pre-stressed in an end position, so that pivoting in and out the component is not performed via changing the current direction, but only by switching on and off the current supply into the electric coil.
In another preferred embodiment the at least one inner magnetically active element is a magnet or a soft-iron core.
In another preferred embodiment a moving coil drive with an electric coil and an anchor is arranged in the inner part of the housing, the anchor being arranged therein axially movable and being connected to the force transmission element.
In this embodiment is, thus, no magnetic coupling acting from the outside through the housing to the inward is provided, but as an actuation device for pivoting in and out the optical component in the inner part a moving coil drive, i.e. an electric coil is arranged, in which an anchor, e.g. a magnet or a soft-iron core is arranged axially movable. The electric coil must then, however, be supplied with current from the outside through the housing. By changing the current direction, the anchor connected to the force transmission element is axially moved to-and-fro, whereby then the optical component is pivoted in and out. Here, the anchor can also be connected to a back-force spring so that the actuation of the optical component is performed by switching on and off the current. The advantage of this embodiment is a further reduction of the radial dimension of the device, as an outer actuation element at the housing of the device is not necessary. In the inner part, also a double coil with a respective winding for each position of the optical component may be provided, wherein then by corresponding control of the corresponding winding, pivoting in and out of the optical component is actuated.
An endoscope according to the invention, which is particularly used for photodynamical diagnosis, for therapy or for fluorescence diagnosis, has a device according to the invention of the type or types described before.
It is then preferred when the device is arranged at the proximal end of the endoscope in an optical head between the eyepiece lens and the cover glass of the eyepiece.
It is here advantageous that there is enough place for the device at this location of the endoscope, and that the optical component, e.g. a filter, is located far enough from first image planes, so that possible contaminations of the component, e.g. dust particles, are not imaged.
In another preferred embodiment the housing of the device forms the housing of the endoscope.
This measure has the advantage that the housing of the device is an integral part of the endoscope housing, whereby it is made possible to construct the endoscope housing altogether hermetically tight and, apart from that, to construct the endoscope housing itself radially narrow.
In another preferred embodiment the housing is hermetically tight.
It is here advantageous that the endoscope can be sterilized in an autoclave, so that moisture or contaminations cannot enter the inner part of the housing. The hermetically tight embodiment of the housing is, on the one hand, reached by the magnetic coupling, on the other hand, by the construction that is integral with the housing of the endoscope of the device.
Further advantages can be taken from the following description and the enclosed drawings.
It is to be understood that the features mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention.